Machine keeps stopping mid-run...short in the cord?

I use the Barudan BEVY-Z1504C, SN 4106362L07. Recently, the red stop button on my machine popped out and I am not sure how to pop it back in. Ever since that happened, my machine has been really touchy. It will randomly stop mid run and beep like there is an error. Sometimes, it will even start to back stitch/rewind so that when I push start, it goes over what it has already sewn. Usually if I press start, it will start right away, but sometimes I have to press start several times before it will register. Is it possible that this is an issue with the wiring? Perhaps a short somewhere?